The number of sinks in a given DEM is normally higher for coarser-resolution DEMs. Learn more about removing or filling sinks. Sinks, being areas of internal drainage, prevent downslope flow routing of water. These are more commonly natural features and are less detrimental to the calculation of flow direction.Įrrors such as these, especially sinks, should be removed before attempting to derive any surface information. Likewise, a spike, or peak, is an area surrounded by cells of lower value. Some of these may be natural, particularly in glacial or karst areas (Mark 1988), although many sinks are imperfections in the DEM. A sink is an area surrounded by higher elevation values and is also referred to as a depression or pit. Visualization of a raster DEM surface.Įrrors in DEMs are usually classified as either sinks or peaks. Other factors affecting accuracy are data type (integer or floating point) and the actual sampling of the surface when creating the original DEM. The accuracy of this data is determined primarily by the resolution (the distance between sample points). This data is used as input to quantify the characteristics of the land surface.Ī DEM is a raster representation of a continuous surface, usually referencing the surface of the earth. The most common digital data of the shape of the earth's surface is cell-based digital elevation models (DEMs).
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